GRE
Card Set Information
Author:
chellen12
ID:
51723
Filename:
GRE
Updated:
2010-11-26 00:35:30
Tags:
equations
Folders:
Description:
math equations
Show Answers:
area of triangle
1/2 base x height
pythagorean theorem
only for right triangles
a
^{2 }
+ b
^{2 }
= c
^{2}
right triangle ratios
(4)
3:4:5
5:12:13
s
: s : s/2
s
: s/3 : 2s
area of square
(2)
s
^{2}
1/2 d
^{2}
^{ }
d=diagonal
area of rhombus, 4 equal sides, 4 angles that aren't necessary right angles
1/2 d1 d2
area of parallelogram
2 opposite and equal pairs of sides
base x height
area of rapezoid
1/2 (b
_{1}
+ b
_{2}
) x h
total interior angle
(n-2) 180
n=number of sides
average measure of one angle in polygon
(n-2)180 / n
volume of polygon
area of the base x height
volume of a cylinder
(pie r
^{2}
) height
total surface area of a cube
6e
^{2}
total surface area of rectangular solid
2(l w) + 2 (w h) + 2 (h l)
total surface area of a cylinder
(circumference x height) + 2(pie r
^{2}
)
distance between 2 points
/ (x
_{2}
- x
_{1}
)
^{2 }
+ (y
_{2}
- y
_{1}
)
^{2}
circumference of circle
2pie r
pie d
area of circle
pie r
^{2 }
length of an arc
1. find the circumference of the circle (2pie r, pie d)
2. put the degree measure* of the arc over 360, reduce fraction
3. multiply circumference by the fraction
area of a sector
1. find area of the circle (r
^{2}
)
2 . put degree measure* of sector over 360, reduce
3. multiply the area by the fraction
equations for FOIL
(a+b)
^{2 }
= a
^{2}
+ 2ab + b
^{2 }
(a-b)
^{2 }
= a
^{2}
- 2ab + b
^{2 }
(a-b)(a+b) = a
^{2}
- b
^{2}
^{ }
find probability
number of possible desired outcomes/ number of total possible outcomes
find distance
distance = rate x time
time = distance/ rate
etc
average
sum/ number of terms
average common sense way
average is 90
numbers: 89, 88, 93, 92 90
-1, -2, +3, +2
= +2
need to get 88 to get average (subtract the number extra or add number needed)
percent increase or decrease
number increase or decrease/ original whole
interest problems
PRTI
Principal x Rate x Time = Interest
principal:amount money begin with
rate
: interest rate you're earning on the money, expressed as a decimal
time
: amt of time (years) money left in account
interest
: amt of interest earn on the investment
work
time put in/ capacity, time to do the whole job